Machines for helically winding strips of material into a pipe, tube, or other form of tubular objects are known. These machines typically receive a strip of material, e.g. a continuous strip, bend that material into a loop, and concurrently connect the newly formed loop onto an edge of an incoming portion of the strip. This process results in a helically wound tubular object which, depending upon the material of the strip, is suitable for a variety of uses. Tubular objects formed in this way are currently used as conduits, sewage pipes, or reels, just to name a few.
These machines usually include a circular rolling surface which receives the material and bends it into a loop. This rolling surface can comprise of a circular arrangement of rollers or a circular metallic band. The rollers or metallic band defines the radius of the formed tubular object.
The strip is typically fed into a machine along a bottom portion of the rolling surface and travels along the rolling surface to form a loop. As additional portions of the strip are fed into the roller assembly, an edge of the newly formed loop is guided to overlap an incoming strip portion along an edge. The overlapping edges are then connected so that the formed loop is eventually completely connected to an incoming portion of the strip.
The formed loops attach to the incoming strip portion in many ways. Some apparatus apply layers of adhesive along the edges of a strip and apply pressure along overlapping edges to adjoin the two. In more heavy duty applications, the strip is formed of a flexible plastic material having connecting structures incorporated along its edges. In these cases, the engaging structures on overlapping portions sealingly engage each other to sealingly connect the overlapping portions.
While the prior art is currently capable of making tubular objects from a continuous strip of materials, most of the prior art references are only capable of making tubular objects of one size. In many instances, tubular objects of different diameters are required and so the prior art necessitates either the use of only one size pipe for all applications or the use of multiple machines.
In many cases, the tubular objects produced are heavy duty pipes that provide a pathway for fluids or carry cables, and other structures. Often, newly wound pipes are directly inserted within preexisting underground piping or tunnels as they are formed. The appropriate diameter pipe is typically dependant upon the job site.
However, a new pipe forming machine is typically needed whenever a pipe of a different size is needed. The expediency of setting up and carrying just one machine for a given job, or the cost of additional pipe forming machines often prevent the use of multiple machines. As a result, the ideal diameter of pipe for a given site may not be used.
Consequently, there is a need for a pipe forming apparatus which is capable of being easily adjusted to create pipes of varying diameters from readily available strip material.